To Be Young, Gifted And Building The Bomb

A memoir of the Manhattan Project

July 24, 2005|By Murray Peshkin, a semi-retired senior physicist at the Argonne National Laboratory. He lives in Elmhurst.

On top of all the divisions was the laboratory director, J. Robert Oppenheimer. He was one of the country's leading scientists at that time, and his staff included several others who were at least as accomplished. They included Enrico Fermi, who had led the team that developed the world's first nuclear reactor, without which the Manhattan project could not have been undertaken; Luis Alvarez, who later invented the ground-controlled approach that all major airports use to guide planes in for landing; and Robert Wilson, the founding director of Fermilab.

Being at the very bottom of the heap, I was put to work performing numerical computations with an electric desk calculator, a marvel of rods and wheels that could add and subtract, multiply and divide. All day long I crunched 10-digit numbers and wrote them on spreadsheets.

I was solving differential equations that were needed to predict the critical mass of a bomb under various assumptions about the many unknown properties of the nuclei in the bomb material.

Then I became the beneficiary of a second stroke of good luck. The renowned 27-year-old physicist Richard Feynman needed an assistant and he selected me to work for him. Working for Dick Feynman was exciting; he was like no other person I have met before or since. I was still spending almost all my time crunching numbers and the truth is that if Feynman had had a programmable pocket calculator that you can buy today for $25, he would not have needed me. But he didn't have one, so there I was. He did more than supervise my number crunching; he told me about other scientific issues with which he was involved, some related to the Manhattan Project and some not. He also showed me how to pick the primitive locks that were commonly used on file cabinets at that time, one of his pastimes at the lab. I think he did all that both out of general kindness and to motivate me by making my work interesting.

Through Dick's office there passed a virtual parade of the leading scientists at Los Alamos, as well as some visiting consultants. They wanted the benefit of his ideas and his judgments. Often, he invited me to listen.

On one occasion, Feynman's visitors were Hans Bethe and the mathematician John von Neumann, who sometimes came to Los Alamos as a consultant. Johnny, as all called him, was one of the pioneers of quantum mechanics, the inventor of game theory and of the first truly mathematical theory of economics, and one of the leading theoreticians in the early development of electronic computers. His mathematical prowess was legendary and all revered him.

Bethe and Von Neumann had been kicking around an idea for an alternative bomb design in case the current ideas didn't work well, and they wanted to know the critical mass in that complicated design. Such a calculation was far beyond our computational abilities at the time. Feynman listened to the question and asked "Why me?" It was not a complaint. It meant, "Why do you think I can solve such a problem any more than you can?" Addressed to Bethe and Von Neumann, that was a reasonable question.

One of them answered, "Nobody can calculate that, so we want you to guess." That measured their respect for Feynman's insight.

After we both left Los Alamos, Dick became one of my graduate-school professors at Cornell. His courses were a joy. Often, long-understood phenomena that seemed routine would become exciting when he presented his uniquely insightful way of looking at them. His way was always simpler and more physical than the standard way, leaving us to wonder why we hadn't thought of that. He used no book and gave few references. It all came from his head. Asked for references, he would say, "I'm trying to train physicists, not librarians."

Ironically, while any competent student could learn physics wonderfully well from Feynman, most could no more learn how to do physics from him than they could learn to dance by watching a ballerina. Only he could do it his way. His idea of a mathematical proof was to give two examples. With Feynman's insight, he could choose the examples so that they tested all the possible loopholes. When we grumbled that his proof lacked mathematical rigor, he said, "D'ya know what rigor mortis means? It means, 'Died of too much rigor.' "

Feynman had very few doctoral students of his own. I studied under Hans Bethe, as did most of my fellow theoretical physics students, but Bethe and most of his students were working on Feynman's then-new theory of quantum electrodynamics, for which Feynman would later be awarded the Nobel Prize; and the most original part of my thesis grew out of a chance conversation with him late at night in an Ithaca coffee shop. He simply tossed out one of his beautifully simple ideas. The mathematician Mark Kac, who knew Feynman well, wrote in his autobiography that there are two kinds of genius-the "ordinary" genius, who seems to be just like you, only much better, and the magicians. I knew who the magician was.